Contents of the SWITCH.DOC file

Many people think that the only practical difference between MS-DOS and PC-DOS lies in GWBASIC.EXE vs. IBM's BASIC.COM and BASICA.COM, and, therefore, that the difference is far from critical.

Wrong!

To begin with, the value of IBM BASICA should not be underestimated. If you want to appreciate the difference with GWBASIC, run any music program under both. A BASIC program called BACH, which plays J. S. Bach's Preludium, from the Partita No. 2 for unaccompanied violin, is excellent for this test, and can be found in most BBSs.

But there's a PD program going around, called MOVBASIC which, when run in an IBM computer or 100 per cent compatible, processes IBM BASIC and/or BASICA so that these will run in "clones". Thefore, the BASIC interpreter is no longer an all-important consideration.

Actually, there are VERY GOOD reasons for switching from MS-DOS to PC-DOS that have nothing to do with BASIC. Indeed, there is IBM hardware that WILL NOT RUN under MS-DOS. The IBM 3.25" external diskette drive is a case in point. Then, there's also some high-caliber IBM software that either will not run, or cannot be installed, under MS-DOS.

While some of these incompatibilities are more apparent than real, and can be circumvented by a more or less knowledge- able user, many a "clone" owner has sold his brand-new compatible, and spent the extra money for "the real thing", in the mistaken belief that his MS-DOS machine was far less compatible than he had thought.

The truth is that most "clones" will accept, and operate satisfactorily under, PC-DOS, except for BASIC -- if the owner hasn't gotten hold of MOVBASIC yet...!

But, once they have their hard disk formatted and setup with MS-DOS, with a good 25 to 50 per cent of capacity taken up by carefully designed subdirectories chuck full of their favorite software, the idea of having to re-partition and re- format the darn thing is enough to keep them awake for nights, trying to make a decision.

The fact is that you don't have to disturb your hard disk organization to switch from MS-DOS to PC-DOS, and this is where SWITCH comes in.

How to Use SWITCH: ------------------

SWITCH completely automates the change from MS- to PC-DOS. Just follow these simple instructions:

(1) Copy SWITCH.COM to your hard disk. (2) Boot your computer with a diskette containing the version of PC-DOS you want to change to. (3) Leave your PC-DOS diskette in drive A (although you can put it in drive B, if you have it and have a valid reason to justify the minor inconvenience of swapping after booting). (4) Make sure the PC-DOS diskette contains all of the DOS utilities whose MS-DOS counterparts are already in your hard disk (including, of course, SYS.COM and COMMAND.COM), plus the DOS utility REPLACE.EXE (see WARNINGS below). (5) Log on to the hard disk and invoke SWITCH.COM in the usual manner (type SWITCH at the DOS prompt and press Enter). (6) Carefully answer the four simple questions and watch SWITCH do its job in a matter of seconds.

Warnings: ---------

(1) SWITCH has been successfuly tested to switch from MS-DOS 3.10 to PC-DOS 3.10 and to PC-DOS 3.20; and from MS-DOS 3.20 to PC-DOS 3.20. It should also work in the opposite direction, that is, to transfer from PC-DOS 3.10 or 3.20 to MS-DOS 3.20 (although we don't see why anyone would want to do any such thing.)

(2) SWITCH will also work from floppy to floppy, and from hard disk to floppy (e.g., when you want to change the version of DOS in a copy-protected floppy that cannot be reformatted).

(3) SWITCH will NOT transfer MS-DOS 3.10 to a PC-DOS 3.20 disk, and presumably will not transfer PC-DOS 3.10 to an MS-DOS 3.20 disk. In other words, switching to an EQUIVALENT or HIGHER version of DOS should present no problem; but switching downward probably won't work.

(4) If the switch is to a version 3.1x or lower, REPLACE.EXE will NOT work. The two system files will be transferred, but after doing this, SWITCH will end with an error message, and replacing COMMAND.COM and the other DOS utilities will have to be done by hand (COPY A:*.* C:\).

(5) SWITCH should NOT be able to transfer a 3.xx version of DOS to a DOS 2.xx disk, or vice-versa.

(6) SWITCH will NOT transfer PC-DOS to disks equipped with "special" versions of MS-DOS (i.e., Xerox MS-DOS, or any other whose system files are not named IO.SYS and MSDOS.SYS. For instructions on how to transfer PC-DOS to any such disk, send $5.00 and a self-addressed, stamped envelope to:

Typically, these situations would cause SWITCH.COM to fail and end with an error message:

(1) The TARGET disk contains a "special" version of MS-DOS (see supra, "Warning 6), or no DOS at all, or a version other than the one you indicated when answering the prompts.

(2) Same as (1), if applicable to the SOURCE disk.

(3) Errors in answering the prompts (e.g., giving Z: as the TARGET or SOURCE disk).

(4) If switching to DOS 3.20, the presence of read-only DOS utilities in the TARGET disk, during the REPLACEment phase.

If SWITCH ends with an error message, the following information will help you understand the situation -- and correct it if possible:

Line 380 refers to the TARGET disk, and Line 390 to the SOURCE disk.

Codes: ------

53 File not found - The disk has no system, an incomplete system, or a special version of the DOS system.

61 Disk Full - If the version you want to transfer occupies more disk space than the one already installed in the TARGET disk, there may not be enough room for it. Consider deleting a few files, preferrably from the top of the directory.

70 Permission Denied - TARGET disk is write-protected, or one of the REPLACEd files (if swithing to DOS 3.20) is a Read- Only file. The latter does not apply to the two system files.

71 Disk not Ready - The drive to which this code applies is empty, or door is open, or disk is badly damaged.

Disclaimer: -----------

Under normal circumstances, the worst that could happen is that SWITCH should not accomplish its purpose. However, you use this program at your own risk, and the author assumes no liability for any damages that may arise directly or indirectly from such use.

Request: --------

Requesting a shareware donation is an exercise in futility these days. Consequently, all I ask is that, if this program helps you in any way, you let me know by leaving E-Mail at any Fido or Opus BBS.